Question

Number of molecules in 1 L of water is

Answer 1

The liter of water has 1000 grams. The number of moles is 1000/18 = 55.556 moles. The number of molecules is therefore 6.022*1023 * 55.556 = 3.346*1025 molecules. The number of atoms is 3 times larger because each molecule has three atoms, so there are 1.0038*1026 atoms in a liter of water.

Answer 2

Molecular mass of water (H2O) = 2×1 + 16 = 18g

Given volume of water = 1L = 1000ml

Density of water = Mass / Volume

Mass = Density × Volume

Mass = 1gm / 1ml × 1000ml

Mass = 1000gm

Moles of water = Given Mass /Molecular Mass

= 1000/18

= 55.55

Molecules of water = No. of moles of water × Avagadro no. of molecules

= 55.55 × 6.02 × 10²³

(Please refer to the above photo for more clear understanding )

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